Sometimes entangled

Trapping two laser-cooled calcium ions has allowed scientists in Japan to demonstrate quantum interference, not of particles nor of waves per se, but of energy in the form of phonons. The phenomenon could have implications for the development of ion traps in quantum information processing and quantum computation. This quantum interference effect, well known with photons, has not, until now, been observed with phonons, the units of vibrational energy that arises as atoms oscillate within condensed matter. The Osaka group's demonstration of this phenomenon could allow quantum simulation to be carried out with phonons and allow quantum interface research to be undertaken.